On June 8, the Food & Drug Administration (FDA) announced good news about cervical cancer prevention. Following successful clinical trials, a vaccine called Gardasil was approved to ward off the strains of the human papilloma virus (HPV), the main cause of cervical cancer. The impact of the vaccine could be huge, given that cervical cancer is the second most common cause of cancer death in women worldwide, responsible for about 240,000 deaths per year.
But the HPV vaccine is not be recommended for every woman, which means that it may not be right for you. As with any important health issue, you should discuss the new vaccine with your doctor. But to help you better understand the cancer and how to prevent it, Prevention.com asked cancer researcher Dr. Doug Lowy, M.D. to answer some common questions about the vaccine. Dr. Lowy is chief of the laboratory of cellular oncology at the National Cancer Institute, specializing in HPV and cervical cancer.
What is HPV and how does it spread?
HPV is the most common kind of sexually transmitted virus, affecting over 50 percent of sexually active adults. There are more than 80 types of HPV. Some types cause irritation, genital warts and other kinds of lesions. Other HPV types–classified as “high-risk” types–can cause cervical cancer.
Is it possible to have HPV and not know it?
Yes, many HPV infections go undetected. Your immune system is capable of clearing the virus on its own within six to twelve months, so in the absence of symptoms, you might never know you had it–and passed it along. The Centers for Disease Control and Prevention (CDC) estimates that 20 million people are currently infected with HPV and that, by the age 50, at least 80 percent of women will have had an HPV infection.
How can a virus cause cancer? Isn’t this unusual?
If the immune system isn’t able to clear the infection and the virus lingers, HPV can cause genetic changes in cells in the cervix, affecting their ability to control normal growth. When looking at all kinds of cancer, this sort of trigger is unusual: viral infections are not considered a common cause. But there are other examples of cancer-causing viruses, including hepatitis C, which can result in liver cancer.
Is cervical cancer caused solely by HPV?
HPV is a factor in every case of cervical cancer. But not every woman infected with the cancer-causing strains of HPV will actually develop cancer. Science doesn’t fully understand the other factors that contribute to cervical cancer, says Dr. Lowy. But it appears that women who smoke and who have many pregnancies have a higher risk. So are women who have compromised immune systems, such as women who are HIV-positive or who are kidney-transfer patients on medication to suppress immune response. A family history of cervical cancer does not appear to be a risk factor.
Who should get the HPV vaccine?
In approving Gardasil, the FDA does not make recommendations regarding its implementation. That’s the job of the CDC’s Advisory Committee on Immunization Practices, which is scheduled to meet within a few weeks after FDA approval. But the data submitted from the clinical trials involved women ages 9 to 26, with the best immune response seen among the youngest study subjects–not only because the adolescents had little to no sexual activity but also because vaccines in general tend to “take” better among young people. So it stands to reason that the vaccine will be recommended for females between the ages of 9 to 26. That’s not to say “that the vaccine will be illegal to administer to older women,” says Dr. Lowy. But there’s no data suggesting that it would be effective and as such, insurance policies would probably not cover it for women over 26.
Does getting the vaccine guarantee that I won’t develop cervical cancer?
No. Gardasil was formulated to vaccinate against the two types of HPV that are responsible for 70% of all cervical cancers. The remaining 30% of cervical cancer cases are caused by other types–against which Gardasil offers no protection. Further and like any vaccine, it is not protective against a virus that you already have, so if you are infected at the time of your vaccination, Gardasil will not work.
If I get the vaccine, will I still need to have a regular pap smear?
Yes! And this message is an important part of a public-service campaign about the vaccine. Pap smears as a means of cervical cancer prevention are crucial, given that Gardasil only offers protection against the HPV types that cause 70% of all cervical cancers.
Will men be vaccinated?
Merck has ongoing trials looking at the effects of Gardasil for protecting men from HPV. It is likely that the FDA will consider approving the vaccine for men: even though men don’t develop HPV-related cancers, they do spread the virus to women.
For more information about the HPV vaccine, cervical cancer and how often you should schedule a pap smear, go to CDC.gov.
-by Diane di Costanzo